Process of producing alkali-metal hydroxids directly from alkali-metal chlorids.



" UNITED STATES PATENT oFmoE,

JULIUS KERTFN OF'DELLBRUCK, NEAR COLOGNE, GERMANY.

PROCESS OI PRODUCING AL KALI-METAL HYDROXIDS DIBECTLY FROM All;KAI.| 1I-MIE'JSAL CHLORIDE.

1,072,010. Specification of Letters patent. K0 Dravflng To all whom it may concern:

Be it known that I, JULIUS Knnsrnu, at citizen of the Gei-man Empire, and residing at Dellbru'ck, near Cologne-on-theRhine, Germany, have invented a certain new and useful Improved Process of. Producing Alkali-Metal Hydroxids Directly from Alkali-Metal 'Chlorids, of which the following is a specification. I

My 'inventionielates to processes of 'producing alkaline hydroxids directly from alkali metal chlorids, andconsistsinefiecting the conversion of the latter by means of hydroxid of lead.

Hitherto it was generally held that by 'droxid of lead exercised no action 'on alkali (Cf. Lunges Handbuoh metal chlorids. (/vr Sodzzimi'usTrio, 3rd edition, vol. 3, page 197, line My own exhaustive re-v searches have, however, led to the surpris ing result thathydroxid of lead is almost qm intitalively converted by means of the alkali metal chlorids, and this reaction therefore fullillsto a great extent the prin cipal requirement desired of a commercial process.

Further advantages of my process are, firstly, that thc chlorin prescnti n the alkali metal 'chlorids is not lost, and, secondly, that the. chlorid-of lead which forms during the reaction can be recdnverte'd into .hy-

droxid of load without difficulty or appre ciablo loss and can be used again in this form.

The known modcs of producing alkali metal hydroxids chemically directly from' their cl1lorids,c. g. by means of zinc oxid or litharge the above cited handbook,

pages"193-216), have very various defects attaching to them. In the first place the yield is very poor; for example, in the oxid of lead; process, at most of the sodium chlorid is' converted. .into caustie soda. Further, the oxid of lead can he recovered only at considerable loss from the chlorid of lead produced during the reaction, and,

in addition, this recovere oxid has a much weaker reactive eiiect than'thoriginal.

Another undoubtedly great advantage of my process is that the agents. employed for recovering the hydroxid oflead, i. a. nitric acid and ammonia, are recovered in the fornrof a valuable product, viz nitrate of ammonia. I

. The said process is preferably car'riedout as follows :A dilute aqueous solution of 'the alkali metal chlorid having the hy- (l['0X1(l of lead suspended therein is heated for a short time at a temperature when simmering occurs, the solution bein stirred around the whole time. About 150 partsof represented by the following. equa-v parts hydroxid of lead.- The basic chlorid of lead which results is separated in a suit able manner firom the alkali lye, washed, and then dissolved i'n'nitric acid. The solutrate and hydrochloric acid dissolved in it, 1s then eynporatcd to dryness, the hydro. chloric acidbeing given'off and condensed;

ammonia from the lead nit-i te solution and can be again used to convert a furthbr line hydroxid.

lute aqueous'solution of the alkali tmetal chlorids having the hydroxidof "leadsues: pended therein,- the application of h'eat'is tures, though much more slowly than the application of heat.

I claim:- l

1. A. process of producing alkali metal hydroxide directly from alkali metal'chlolution of an alkali metal chlorid with, hy-

hydroxid containing basic chlorid of lead is obtained, and in separati the cfhlorid of lead from the alkali metal ydroxi'd.

hydroxids directly from alkali metal ch10? rids which consists in heating an aqueous solution of an alkali metal chlorid containing hydroxid of lead, Whereby'an alkali metal hydroxid containing basic chlorid eof lead is obtained, andin separating the chlorid of lead from the alkali metal hydroxid. 3. A recess of reducing alkali metal hydroxi 5 directly liom alkali metal chlorlds which consists in heatingjan aqueous potassium chlorid, or about HO parts 80-:

duun chlorid will be mixed With ab91 h1500 v .tion thus obtained, which containsle'ad ni- Although it is preferable to heat the di-.

droxid of lead, wherebyanalkali metal- Patented Sept.2,1313,. Application filed Qptober 18, 1912. Serial Roi 726,544. 7

the'hydroxid of load is-thcn precipitatedby quantity of alkali metal chlorid into alkanot essential to my process; The reactiondescribed takes place at ordinary temperavids which consists in mixing an aqueous so 2; A process-of producing alkali-metal .106

' solution of an alkali metal chlorid containrid of';lead from the alkali metal hydr0xid,'

in recovering the hydroxid of lead from the basic chlorid of lead, and in converting another aqueous solution of said alkali. metal ehlorid into an alkali metal hydroxid by means of the recovered hydroxid of lead, 10 and so on.

In testimony 'whereof, I afiix my signature in the presence of two Witnesses.

JULIUS KERSTEN. 

